Thermostatic control for engines



April 7, 1953 2,633,834

E. c. KIEKHAEFER THERMOSTATIC CONTROL FOR ENGINES Filed Dec. 1, 1950 631 4 1322233 Km J Pzez4 Patented Apr. 7, 1953 UNITED STATES THERMOSTATIC CONTROL FOR ENGINES Elmer C. Klekhaefer, Cedarburg, Wis.

Application December 1, 1950, Serial No. 198,699

3 Claims.

This invention relates to two-cycle, internalcombustion engines and particularly to cooling systems therefor.

The invention provides a thermostatically controlled circulation of coolant which is responsive to the temperature of the coolant and of the engine crankcase and crankcase induction fuel system.

An object of the invention is to improve the temperature control of the engine.

A more particular object is to adjust the temperature regulation of the engine in relation to the intake air temperature.

Another object is to ensure adequate cooling of the engine at low speeds without over-cooling.

Another object is to provide a variable temperature control according to the operating conditions and atmospheric temperature.

Another object is to provide a thermostatic control unit which is more immediately responsive to temperature changes.

These and other objects and advantages will be more fully set forth in the following description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

In the drawings:

Figure l is a side elevation of the upper end of an outboard motor with parts thereof broken away and sectioned and the water pump shown diagrammatically;

Fig. 2 is a front elevation of a portion of the motor with parts thereof broken away and sectioned; and

Fig. 3 is an enlarged transverse section through the thermostatic control unit taken on line 3--3 of Fig. 1.

The engine I of the outboard motor shown in part in the drawings includes the crankcase 2 and cylinder block 3 which are supported on the upper end of the hollow drive shaft housing 4 of the motor.

The pump 5, shown schematically, is carried at the lower end of housing 4 and is disposed under water in normal operation of the motor so as to be in constant supply of water for cooling of the engine, as will be described. Pump 5 is operatively connected to engine I by the drive shaft 6 and is driven by engine I directly and at all times while the motor is in operation.

Engine l shown is of two-cycle operation and employs crankcase precompression of the fuel mixture delivered by carburetor l secured to crankcase 2. Crankcase 2 is provided with individual crank chambe s 3 Which receive the fuel PATENT OFFICE mixture separately from carburetor I for precompression and transfer to the respective cylinders 9.

Parts of block 3 form a jacket around cylinders 9 to provide the coolant chamber I0 closed by the plate ll. Chamber l0 surrounds the upper ends of the cylinders 9 to receive a coolant, as will be described, and to maintain the engine at the desired operating temperature.

The pipe [2 connected to the discharge outlet of pump 5 extends upwardly within housing 4 to the engine. The upper end of pipe I2 is connected at the lower end of crankcase 2 with the passages l3 therein and in block 3, passages I3 are in registry to provide communication between pipe l2 and the lower end of chamber [9.

The conduit l4 cast in crankcase 2 extends from the upper end of the crankcase adjacent the cylinder block 3 and downwardly to open from the lower end of the crankcase into the upper end of drive shaft housing 4. The plug 15 closes the upper end of conduit l4 and is seated after the plug l6 has been driven into the conduit to close the latter adjacent the cavity I1 formed in the side of the crankcase.

The two holes l8 drilled in the adjoining faces of block 3 and crankcase 2 open into the upper end of chamber l0 and conduit [4, respectively, and provide a passage therebetween.

The upper portion of conduit I4 communicates with cavity I! through a hole drilled in crankcase 2 from the cavity into the conduit above plug Hi to provide the passage l9. The drilled passage 20 from conduit 14 immediately below plug [6 opens from the crankcase adjacent to cavity 11.

The cover 21 secured to crankcase 2 closes cavity I1 and the open end of passage 20. The recess 22 in cover 2| overlies cavity I! and passage 20 to provide communication therebetween and between the upper and lower portions of conduit I4.

The thermostatic valve control unit 23 includes and is secured within cavity I! by the circumferentially flanged member 24 disposed between cover 2| and the crankcase. Member 24 provides a valve seat having a port 25 which is closed or controlled by the valve 26. The bellows 27 is responsive to temperature variations which expand or contract the bellows and through the valve stem 23 connecting the bellows and valve disc 26 serves to operate or move the latter with respect to member 24. The control unit is adapted to close valve port 25 at and below a predetermined temperature thereby closing cavity l1 and communication between the upper and lower portions of conduit [4 and above the predetermined temperature referred to, valve port 25 is open.

The temperature at which the control unit opens or closes port 25 should be the optimum operating temperature of the water leaving chamber lll as found by test.

When the motor has been standing and has cooled. to atmospheric temperature, port 25 will be closed. Generally the coolant chamber l and the passages will be drained of water. When engine I is started and the motor is in operation with pump under water, the pump delivers water coolant through pipe l2 and passages [3 to chamber l0.

As chamber I0 is filled the entrapped air in the chamber is allowed escape through conduit l4 and passage l9 by valve unit 23 and through the small opening 29 drilled in valve disc 26 to open from port 25. Where a complete airtight closure of port 25 is not effected by the valve unit employed, opening 29 may be dispensed with. Suthcient leakage should be allowed or provided so that in addition to allowing the escape of air, a minimum limited circulation of the water from the top of chamber it through cavity ll obtains at all times while the engine is operating.

As the engine heats and the temperature of the water leaving chamber Io approaches the predetermined temperature referred to above, the bellows 2'! expands moving valve disc 26 to open port 25.

As port 25 is opened the greater circulation of water allowed through chamber l0 and effecting a greater heat transfer results in a lowered temperature of the water leaving the chamber which when passing through cavity l1 contracts the bellows and recloses port 25.

In operation, the relation of the rate of circulation and the temperature of the water leaving chamber l0 approaches and is maintained at an equilibrium by the bellows of unit 23. When the engine is operating at high speed and the heat transfer rate equals or exceeds that within the range of control by the valve unit 23, bellows 2'! will remain fully expanded and port 25 fully open for maximum circulation of water through chamber H3 within the capacity of pump 5.

Pump 5 should be of ample capacity for high speed operation and of low pressure so that when port 25 is closed excessive water pressure will not be developed in the system.

When operating the motor in cold weather it is ordinarily found desirable to allow the engine to run at a higher temperature of the coolant to compensate for the greater heat dissipation of the engine into the atmosphere. In the usual temperature controlled coolant system it is necessary to adjust the temperature control for the optimum temperature of the engine carburetion and fuel intake system and of the combustion cylinders in cold weather.

According to the present invention, the infiuence of the air drawn into the crankcase and passing therethrough automatically effects the desired adjustment particularly for extreme weather conditions.

The cold air constantly passing through each chamber 8 of crankcase 2 tends to reduce the temperature of the crankcase. The warm water from chamber I0 passing through the upper end of conduit It to cavity ll, also located in the crankcase, is accordingly cooled in passing adjacent to chambers 8.

In cold weather the thermostatic unit 23 is thus indirectly responsive to the cold air drawn into crankcase 2 and the cold air surrounding the crankcase so that the temperature of the water leaving chamber I0 is increased accordingly. The temperature differential of the water leaving chamber [0 and of the water in cavity ll provides the equivalent adjustment of the temperature control of the water leaving the chamber so that the engine is generally allowed to run at a higher temperature.

The transfer of heat through the metal of crankcase 2 from the discharged coolant water to the intake air in such cases is beneficial to engine performance in assuring a more complete carburetion of the air.

In warm weather no appreciable differential of temperature of the water reaching cavity I1 is effected and the temperature control of the water in cavity l1 approximates the desired temperature control of the Water leaving chamber [0.

Various embodiments of the invention may be employed within the scope of the following claims,

I claim:

1. In an internal-combustion engine, an engine block having a chamber receiving the intake air for and prior to combustion, a combustion cylinder receiving the air from said chamber, a jacket around said cylinder forming a coolant chamber adapted to receive a coolant under nominal pressure for circulation therethrough and to receive the heat of the combustion cylinder, a conduit from the upper level of said coolant chamber for discharge of the coolant therefrom, said conduit passing through said engine block adjacent to said first named chamber, and a thermostatically operated valve at the end of and controlling said passage in response to the temperature of the coolant passing said valve, said valve being adapted to close at and below a predetermined critical temperature and to open at and above said critical temperature, said passage being subject to cooling by the air within said first named chamber adjacent thereto whereby the effective control by said thermostatically operated valve of the temperature of the coolant leaving said second chamber is subject to adjustment in response to the temperature of the air in said first named chamber, and in general to the atmospheric temperature.

2. In a two-cycle internal-combustion engine including a combustion cylinder, a crankcase having a crank chamber for receiving the fuel mixture including air at atmospheric temperature for precompression prior to transfer to the engine cylinder, a jacket around said cylinder adapted to receive a coolant under nominal pressure for circulation therethrough and to receive the heat of combustion, said crankcase having a cavity formed therein adjacent to said chamber and a conduit formed therein communicating at one end with the upper level of said jacket to receive the coolant discharge therefrom and opening at the other end into said cavity, a discharge opening from said cavity, and a thermo static valve unit disposed within said cavity to control the passage therethrough of coolant from said conduit and discharge through said opening and the rate of circulation of coolant through said jacket in response to the temperature of the coolant passing said unit, the coolant approaching said valve unit from said jacket within said conduit and said cavity being subject to variable cooling by the air within said chamber according to their respective relative temperatures whereby the temperature control of the engine by said valve unit is regulated in response to the temperature of the atmospheric air for com bustion passing through said chamber.

3. In an outboard motor, an engine, a pump driven by said engine and disposed in constant supply of water while the motor is being operated, said engine including a block having a chamber receiving the intake air for and prior to combustion, a combustion cylinder receiving the air from said chamber, a jacket around said cylinder forming a coolant chamber adapted to receive a coolant from said pump under nominal pressure for circulation therethrough and to receive the heat of the combustion cylinder, a conduit from the upper level of said coolant chamber for discharge of the coolant therefrom, said conduit passing through said engine block adja cent to said first named chamber, and a thermostatically operated valve at the end of and controlling said passage in response to the temperature of the coolant passing said valve, said valve being adapted to close at and below a predetermined critical temperature and to open at and above said critical temperature, said passage bein response to the temperature of the air in said first named chamber, and in general to the atmospheric temperature.

ELMER C. KIEKHAEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,774,881 Fry Sept. 2, 1930 1,790,578 Foutz Jan. 27, 1931 2,129,846 Knochenhauer Sept. 13, 1938 2,401,646 Johnson June 4, 1946 FOREIGN PATENTS Number Country Date 527,018 Great Britain Oct. 1, 1940 

